The present invention relates to low-fat content, butter-flavored spreads which simulate the flavor, texture, mouthfeel, appearance, and stability of butter and margarine. More particularly, the present invention relates to diet products of this type having a reduction in caloric density of from 50 to 90%, and to processes for preparing them.
The art is replete with prior art attempts to provide low-fat butter or margarine substitutes. Among these is U.S. Pat. No. 3,457,086 to Josefowicz, et al. which teaches the production of a protein-free spread which can contain as low as 35% fat. The patent states that observance of specified conditions is necessary to maintain the emulsion in the water-in-oil form. Unfortunately, products of this type tend to have a watery flavor because of their high water contents and the absence of milk proteins which help impart the desirable butter-like taste of margarine or butter, but which cannot be tolerated in the product because of their emulsion de-stabilizing effect. Moreover, the high water contents tend to make emulsions of this type rapidly break down on hot foods, tending to make foods like toast become soggy and unappetizing. Also, while some consumers have found it convenient to buy large quantities of margarine or butter at sale prices and then freeze them, low-fat spreads based on water-in-oil emulsions cannot tolerate freezing. Upon thawing, the emulsion breaks down with consequential release of its water phase.
Some recent patents suggest that water-in-oil emulsions can be formed with fat contents as low as 25 or 30% to successfully simulate butter or margarine. This has always presented severe problems because the external fat phase tends to become stretched out and the aqueous phase becomes more predominant. For example, U.S. Pat. No. 4,103,037, to Bodor et al. discloses a process for preparing a proteinaceous low-fat spread which is stabilized by a gelling agent, such as gelatin, having a melting point sufficiently high to withstand room temperature yet low enough to allow it to melt in the mouth. This gelling agent ties up all available water into minute solid particles which are dispersed throughout a continuous fat phase. These meltable particles contain the water soluble flavors and salt, and further diminish the flavor impact of these components which are already diminished due to the nature of the water-in-oil emulsion.
The adverse effect of water-in-oil emulsions on flavor impact is so pronounced that this is the problem which was dealt with by Moran in U.S. Pat. No. 4,115,598. Therein, flavor impact for a low-fat spread comprising 35 to 65% by weight of a continuous fat phase and dispersed aqueous phase is said to be improved by specially formulating the water-in-oil emulsion to destabilize in the mouth to release the water-soluble flavors.
Further representative of the state of the art of low-fat spreads is U.S. Pat. No. 4,071,634 to Wilton et al. This patent states that low-fat spreads are generally emulsions of the water-in-oil type and can have fat contents reduced to as low as 30%, as compared to 80% for margarine. It is indicated that problems related to inferior organoleptic properties or emulsion stability are often encountered in these types of products. Apparently, products of this type which are sufficiently stable, have flavor release problems; while those with good flavor release, are insufficiently stable to keep the aqueous phase adequately dispersed under storage conditions. To remedy this problem, Wilton et al. propose a complex emulsion wherein a discontinuous aqueous phase contains phosphatides and a discontinuous, second fatty phase dispersed therein.
Among other attempts to provide low-fat spreads is the approach described by Nijhoff in U.S. Pat. No. 3,418,133. Therein, edible spreads are described wherein a portion of a fat content is replaced by an aqueous solution of carboxymethylcellulose. In Example 2, a margarine substitute is described which is prepared from a 50/50 mixture of margarine and aqueous solution. This product presumably has a fat content of about 40% (i.e., one half that of margarine); however, the type of emulsion is not identified and the emulsions do not remain stable and solid at room temperature.
U.S. Pat. No. 3,809,764 to Gabby et al. discloses essentially fat-free products which are characterized as "emulsions" of polyglycerol fatty esters with an aqueous hydrophilic colloid. Among the products, are those which are said to simulate margarine yet contain fat contents of less than 5%. These products, while fairly flavorful and fat mimetic, are significantly different in overall flavor, texture, mouthfeel, and appearance from either margarine or butter.
Richardson, in U.S. Pat. No. 4,156,021, also discloses low-fat compositions said to simulate margarine. Example III of this patent employs about 7% corn oil. The emulsions are said to be of the oil-in-water type but obtain much of their body from high levels of cellulose fiber, which also adds its characteristic impact on mouthfeel which is significantly different from that of fat.
Other workers have disclosed stable emulsified products containing oil-in-water emulsions, wherein sugars were employed; however, the necessity for sugar made them sweet and clearly distinct from butter or margarine. Among these is U.S. Pat. No. 3,958,033 to Sims et al. which relates to shelf-stable, clear, liquid emulsions. The sugar was essential in these formulations to supply the desired sweetness, adjust the refractive index of the aqueous phase to improve product clarity, and enhance shelf stability. Similarly, in U.S. Pat. No. 4,146,652, Kahn et al. describe stable oil-in-water emulsions containing high sugar levels to obtain microbiological stability. In U.S. Pat. No. 4,107,343 to Petricca the sugar was required for sweetness demanded of the whipped products involved. Thus, despite the disclosure by these patents of stable oil-in-water emulsions with fat contents in the 10 to 30% range, and the disclosure by Sims et al. in Example XXII of a maple-flavored spread, and a confectionary butter cream in Example I of Kahn et al., there is no solution afforded the skilled worker in the low-fat margarine or butter substitute art seeking a product which can successfully reproduce the flavor, texture, mouthfeel, stability and appearance of butter or margarine at a caloric density of 10-45 calories per 14 gram serving, as compared to the 50 or more calories per similar serving for the best low-fat, butter-flavored spreads commercially available to date.